Some researchers have hypothesized that foot fetishism increases as a response to epidemics of sexually transmitted diseases. In one study, conducted by Dr. A James Giannini at Ohio State University[8] an increased interest in feet as sexual objects was observed during the great gonorrheaepidemic of twelfth-century Europe, and the syphilis epidemics of the 16th and 19th centuries in Europe. In the same study, the frequency of foot-fetish depictions in pornographic literature was measured over a 30 year interval. An exponential increase was noted during the period of the current AIDS epidemic. In these cases, sexual foot play was viewed as a safe-sex alternative. However, the researchers noted that these epidemics overlapped periods of relative female emancipation.[9] Sexual focus on female feet was also hypothesized to have been a reflection of a more dominant posture of the woman in sexual-social relations. (The first surviving mention of foot fetish is by Bertold of Regensburg in 1220.)[10]